Telephone system.



' PATENTED MAY 26, 1908.

E. R. OORWIN. TELEPHONE SYSTEM. LPPLIOATION FILED MAY 11 1906 WITNESSES INVENTOQ ER.CORWIN A TTORNE Y 1: nvmus Pzrnu cm, wasnmamlv. D. c

UNITED STATES PATENT OFFICE. I

ELMER It. CORWIN, OF CLYDE, ILLINOIS, ASSIGNOR TO MONARCH TELEPHONE MANUFAC- TURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented May 26, 1908.

To all whom it may concern:

Be it known that I, ELMER R. CORWIN, citizen of the United States, residing at Clyde, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Telephone Systems, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to telephone exchange practice, and has for its general object the provision of simplified mechanism and circuits for governing the operation of calling and supervisory or disconnect signal devices and calling and supervisory pilot signal devices.

By means of my invention I may, through the agency of a single relay associated with each telephone line, a jack of said line, a plug insertible in said jack, and suitable circuit connections, effect, in cooperation with the sub-station apparatus, complete control of line and supervisory or disconnect signal devices and also of pilot calling and supervisory signal devices. I

In practicing my invention, I desirably employ a line relay for each telephone line having two armature switches that are closed upon contacts when the line relay is energized, one of said armature switches serving to close the line signal circuit, while the other armature switch completes one of two gaps in a shunt about the supervisory or disconnect signal device, the other opening in said shunt being established by a plug when it is inserted in the jack of said line. As the line relay is energized during the entire time the subscriber has his telephone off its hook, the shunt about the supervisory or disconnect signal device is maintained intact so that said signal device does not operate or glow, and, in order that a special cut-off relay need not be employed for removing the line signal devices when the operator plugs into the jack, the same shunt or practically the same shunt or a portion of the same shunt that is used for shunting the supervisory signal device is also preferably used for shunting the line signal device. Each line signal device, therefore, is shunted as soon as the operator answers the same. The telephone line just spoken of is understood to be the calling telephone line, but the control of the signal devices associated with the called telephone line is very much the same, it, of course, being understood that in the case of a called telephone line the line signal device of such line is not operated when the called subscriber removes his telephone from its hook, for this operation has been guarded against by the operator in engaging the connecting plug with the jack of the called line. In other Words, in the preferred embodiment of the invention, in so far as the control of the signal devices is concerned, the connecting ends of the cord circuits are preferably like the answering ends thereof.

A subscriber, in initiating a connection, operates his line relay (which remains operated while the calling subscribers receiver is removed from its hook), thereby completing a local circuit at the exchange that includes the line signal device, a portion of which local circuit is common to a plurality of such circuits, which common portion contains a pilot call signaling device, the part of the pilot signaling device included in this common portion of the circuit being desirably a low resistance relay whichcontrols the operation of an armature switch that determines the illumination of a pilot lamp. When the line relay is energized, a special short circuiting switch, operated by the line relay, is closed to close one gap in the shunt about the line signal device, the other gap of which is closed by the inserted plug, as stated hitherto.

As stated hitherto, the supervisory or disconnect signal device has, by this extra line relay armature switch and the plug and jack contacts, established a shunt about the supervisory signal device, it being still remembered that the line relay is energized while the subscriber has his telephone removed from its hook, but when the subscriber restores his receiver to its hook, the armature switch determining the opening at one portion in the shunt is released to open the shunt at this portion, whereby the supervisory or disconnect signal device is included in circuit, a part of which circuit, as is understood, being established by the plug and registering contact of the jack into which .the plug has been inserted. The 0 erator, in response to the clearing-out signal, withdraws the plug, and thereby efiaces the said signal. It will be also understood that while the shunt about the linesignal device has also been opened at one of the line relay switch contacts when a subscriber restores his receiver upon its hook, the other line relay switch contact is also opened, whereby the line signal device is included in open circuit, so that it does not again effect a signal.

. Each disconnect or supervisory signal circuit desirably contains a portion which is common to a group of supervisory or disconnect signal cirucits, which common portion preferably includes a relay that determines the illumination of a supervisory or disconnect pilot lamp. It will be understood that the shunt is not established about the pilot call signal device until all of the calling subscribers common to said pilot call signal device have had their calls attended to. It will also be understood that the shunt about the supervisory pilot device is not removed until all of the subscribers connected with the cords common to said supervisory pilot device have restored their receivers, and that the pilot signal device is not restored to normal or non-indicating position until all of the" plugs of the cords common thereto are withdrawn from the jacks.

My invention finds a large utility in connection with subscribers telephone lines, but I do not wish to be limited in all embodiments of the invention to telephone lines extending from exchanges to subscribers stations, as it is obvious that my invention may have other applications.

I will explain my invention more fully by reference to the accompanying drawing and will point out more clearly advantages of my lnvention in connection therewith, in which I Figure 1 illustrates the invention as applied to telepohne exchange systems including subscribers lines. Fig. 2 is a schematic view more briefly outlining the circuits that are shown in Fig. 1.

Like parts are indicated by similar charactors of reference in both figures.

There are indicated two of many substations, A, B, each in the embodiment of the invention shown, having a transmitter 1, a receiver 2, a call bell 3, a switch-hook 4, a condenser 5, and an impedance coil 6, together with suitable contacts and circuit connections, whereby, when the telephone receivers 2 are upon their switch-hooks, the bells 3, together with the condensers 5, are bridged across the sides of the telephone lines 7, 8, and whereby when the telephone receivers are removed from their hooks, the bridges including said signaling bells are opened and the transmitters are thrown into conductive connection with the lines, whereby battery may be fed thereto through the impedance coil 6, and whereby these currents may be impressed upon the lines at the substations at the transmitters or may be re- .vice 14, the remaining ga ceived atthe receivers. I do not wish to be limited to the precise sub-station circuits indicated' The limbs 7, 8 of the telephone lines are, in multiple switch-board practice, multipled to sleeve contacts or thimbles 9 and tip springs or contacts 10, respectively, of multiple spring jacks, though the invention may be useful in connection with switch-boards that are not multiple switch-boards, in which case but one spring jack need be supplied to a line. In multiple switch-board practice, one of the jacks may act as an answering jack, the answering jacks, as is understood, being suitably distributed among the different sections of the switch-board, the multiple acks being multipled to the several sections of the switch-board, which grouping arrangement, or any other preferred grouping, is well understood.

In the embodiment of the invention shown, the line relays 11 have their windings desirably permanently associated with the corresponc ing telephone lines and the common talking battery 12, the circuit of this-talking battery desirably having one of its poles permanently connected with one side of the subscribers circuit through the relay 1 1, and the other pole connected with the other side of the subscribers circuit through the impedance device 13. When a subscriber removes his telephone, the line relay 11 be comes energized, whereby a circuit through the line signal device 14 of the calling subscriber may be closed by way of a line relay switch 15 and its front contact, said armature switch 15 being desirably, though not necessarily, connected with one pole of a special signaling battery 16, the other pole of which is connected through the line signal device 14 to the front contact of said switch 15. In the portion of the line signal circuit 17 that is common to a group of line circuits, there is included a pilot signal device. In the form of the invention shown, the winding 18 of a pilot signal device relay is included in this common circuit portion 17, the armature switch of this relay governing the circuit condition of the pilot line lamp 19.

On the initiation of a call, a second armature switch 20 is also operated to engage its front contact, this armature switch and its contact closing one gap in a shunt conductor 21 provided for inclusion about the signal dein which shunt conductor 21 is establishe by the sleeve of the inserted plug, which connects the sleeve talking contact 9 of the jack containing the plug with an extra contact 22 in connection with the contact of the armature switch 20, the said sleeve of the plug being also a talking contact. 7

do not wish to be limited to the stated registering contacts of the lugs and jacks for establishing one closure of the shunt circuit.

It will be seen that as soon as the operator responds to a calling subscriber, the signal occasioned by the device 14 is effaced with out the aid of a cut-off relay. In the case of the signal device 14 is in open circuit.

It will be apparent that the calling signal device 14 operated by a calling subscriber cannot again be operated during an established connection, on account of the presence of the plug in the jack corresponding to the call signal device.

When a subscriber restores his telephone upon its switch-hook, his line relay 11 becomes deenergized, whereby the short orshunt circuit 21 is o ened at 20, thereby opening the short or s iunt circuit about the supervisory or disconnect signal device, there being two such devices 23, 24, where double supervision is desired, and it may be assumed that the device 23 corresponds to the calling subscriber and the device 24 corresponds to the called subscriber, for sake of example.

Current from the battery or source 16 is now at liberty to flow through the lamp 23 (or the lamp 24, or both lamps, as the case may be), thereby furnishing a supervisory or disconnect signal to the operator. If it is a disconnect signal, the operator effaces the same by pulling down the connection between the subscribers.

I have indicated a relay 25 in a circuit portion 26 common to a group of lamps 23 which becomes energized, on account of the removal of the shunt 21, when any of the subscribers in connection with the cord circuits having said group of lamps 23 have restored their receivers upon their switch-hooks, whereby the pilot signal lamp 27 becomes energized, the signal occasioned by this device 27 being elfaced, when all of the plugs correspondingthereto are removed from the engaging jacks.

In Fig. 1 of the drawing the parts shown upon the right hand having functions similar to parts shown upon the left hand are given similar characters of reference, with the exception of the su ervisory signal devices, one of which is pecu iar to the calling subscriber and the other of which is peculiarto the called subscriber.

While I have shown two supervisory signal devices, I do not wish to be limited to this number of disconnect signal devices in the cord circuits.

I have not indicated the operators listening and ringing keys and associate apparatus, as these instrumentalities and the functions thereof are well understood by those skilled in the art, and their application to'the system shown is very apparent.

While I have illustrated a multiple switch board system and have shown and specifically described lamps for effecting display of signals, I do not wish to be limited to such character of switch-boards, nor to the use of the lamps for said purposes.

The shunt circuits about the line and supervisory signal devices and thecorreslponding pilot signal devices are desirably of so low resistance as to constitute short circuits about said devices, though I do not wish tobe limited to shunt circuits that have so little resistance as to constitute short circuits, as I consider it to be within the scope of my invention to employ shunt circuits without regard to the degree of resistance contained therein, but of such electrical character as to prevent such an operation of the signal devices about which the shunts are placed as it is desired to avoid by said short or shunt circuits, as herein fully set forth.

I have herein shown a telephone exchange system in which the cord circuits are each provided with two plugs, and I have shown s ring jacks for receiving the answering p u'gs. It is obvious, however, that characteristics of my invention are applicable for other types of telephone exchange systems, and I do not, therefore, wish to be limited to those systems in which link circuits having two manually operated plugs are employed.

While I have shown spring jacks for the tele hone lines, I do not wish to be limited in al embodiments of the invention to such types of connecting switches.

It is obvious that changes may be made from the embodiment of the invention herein particularly shown and described without departing from the spirit of my invention, and I do not, therefore, wish to be limitedto the precise construction and arrangement herein shown, but,

Having thus described my invention, I claim as new and desire to secure by Letters- Patent 1. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, disconnect signal circuits corresponding to the cord circuits, said disconnect signal circuits having a common portion, a pilot signal device included in said common portion, and means in association with the telephone lines extraneous to the cord circuits acting in combination with the plugs and jacks to govern the operation of said pilot signal device.

2. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, disconnect signal circuits correconnect signa sponding to the cord circuits, said disconnect signal circuits having a common portion, a pilot signal device included in said common portion, and line relays in association with the telephone lines acting in combination with the plugs and jacks to govern the operation of the ilot signal device.

3. In a te ephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, disconnect signal circuits corresponding to the cord circuits, each signal circuit including a portion of a talking conductor of a corresponding cord circuit, said disconnect signa circuits having a common portion, a pilot signal device included in said common portion, and means in association with the telephone lines extraneous to the cord circuits acting in combination with the plugs and jacks to govern the operation of said pilot signal device.

4. In a telephone exchange system, the

combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, disconnect signal circuits corresponding to the cord circuits, each signal circuit including a portion of a talking conductor of a corresponding cord circuit, said disportion, a pilot signal device included in said common portion, and line relays in association with the telephone lines acting in combination with the. plugs and jacks to govern the operation of the pilot signal device.

5. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, disconnect signal circuits corresponding to the cord circuits, each signal circuit including or adapted to have included as a part thereof a talking conductor of a jack and an engaging contact of a plug, said disconnect si nal circuits having a common portion, a pilot signal device included in said common portion, and means in association with the telephone lines extraneous to the cord circuits acting in combination with the plugs and jacks to govern the operation of said pilot signal device.

6. In a telephone exchange system, the combination'with telephone lines, of jacks therefor, cord circuits for connection with the jacks, disconnect signal circuits corresponding to the cord circuits, each si nal circuit including or adapted to have inc uded as a part thereof a talking conductor of a jack and an engaging contact of a plug, said disconnect signal circuits having a common portion, a pilot signal device included in said common portion, and line relays in associationwith the telephone lines acting in combination with the plugs and jacks to govern the operation of the pilot signal device.

7. In a telephone exchange system, the combination with telephone lines, of jacks circuits having a common therefor, cord circuits for connection with the jacks, a pilot line signal device common to said tele hone lines, and shunt conductors in connection with said pilot line signal device for eifacing the signals it occasions, which shunt conductors include registering contacts of plugs of the cord circuits and engaging jacks.

81 In a telephone exchange-system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, line signal devices for said telephone lines, shunt conductors in connection with said line signal devices for effacing the signals they occasion, which shunt conductors include registering contacts of lugs of the cord circuits and engaging jac s, and line relays for the telephone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuits and to constitute and establish other connections in said shunt conductorsl 9. In a telephone exchange system, the combination with telephone lines, of jacks therefor,'cord circuits for connection with the jacks, a pilot line signal device common to said telephonelines, shunt conductors in connection with said ilot line signal device for effacing the signa s it occasions, which shunt conductors include registering con-.

tacts of plugs of the cord circuits and engaging jacks, and line relays for the telephone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuits and to constitute and establish other connections in said shunt conductors.

10. In a telephone exchan e system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, line signal devices for said telephone lines, shunt conductors in connection with said line signal devices for effacing the signals they occasion, which shunt conductors include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, said relays hav ing armature switches serving, when operated, to establish the corresponding line signal circuit and to constitute and establish other connections in said shunt conductors, and supervisory or disconnect signaling circuits established by plugs and enga ing contacts of jacks, the signal device 0 each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated.

11. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, a pilot line signal device common to said telephone lines, shunt conductors in connection with said pilot line signal device for effacing the signals it occasions which shunt conductors include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuit and to constitute and establish other connections in said shunt conductors, and supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, the signal device of each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated.

12. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, line signal devices for said telephone lines, conducting media in connection with said line signal devices for efiacing the signals they occasion, which media include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, each relay having armature switching mechanismwhich serves, when operated, to establish the corresponding line signal circuit and to constitute and establish another connection in said conducting media, supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, and a pilot signal device including a conducting portion common to said latter signaling circuits and shunted by the actuated switching mechanism of the lines relays.

13. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, line signal devices for said telephone lines, shunt conductors in connection with said line signal devices for effacing the signals they occasion, which shunt conductors include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuit and to constitute and establish other connections in said shunt conductors, supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, and a pilot signal device including a conducting portion common to said latter signaling circuits and shunted by the actuated switching mechanisms of the line relays.

14. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, a pilot line signal device common to said telephone lines, conducting media in connection with said pilot line signal device for efi'acing the signals it occasions which media include registering contacts of plugs of the cord circuits and engaging jacks, line re lays for the tele hone lines, each relay having armature svvitc iing mechanism which serves,

when operated, to establish the corresponding pilot signal circuit and to constitutejand establish another connection in said conducting media, supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, and a pilot signal device including a conducting portion common to said latter signaling circuits and shunted by the actuated switching mechanisms of the line relays.

15. In a telephone exchange system, the

combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, a pilot line signal device common to said telephone lines, shunt conductors in connection with said pilot line signal device for efiacing the signals it occasions, which shunt conductors include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuit and to constitute and establish other connections in said shunt conductors, supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, and a pilot signal device including a conducting portion common to said latter signaling circuits and shunted by the actuated switching mechanisms of the line relays.

16. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, line signal devices for said telephone lines, conducting media in connection with said line signal devices for efiacing the signals they occasion, which media include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, each relay having armature switching mechanism which serves, when operated, to establish the corresponding line signal circuit and to constitute and establish another connection in said conducting media, supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, the signal device of each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated, and a pilot signal device included in a conductor portion common to said disconnect signal circuits.

17. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, line signal devices for said telephone lines, shunt conductors in connection with said line signal devices for effacing the signals they occasion, which shunt conductors include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuit and to constitute and establish other connections in said shunt conductors, supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, the signal device of each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated, and a pilot signal device included in a conductor portion common to said disconnect signal circuits.

18. In a telephone exchan e system, the combination with telephone Iines, of jacks therefor, cord circuits for connection with device of each of which latter circuits being.

shunted by the switching mechanism of the corresponding line relay when said mechanism is operated, and a pilot signal device included in a conductor portion common to said disconnect signal circuits.

19. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, a pilot line signal device common to said telephone lines, shunt conductors in connection with said pilot line signal device for eifacing the signals it occasions, which shunt conductors include registering contacts of plugs of the cord circuits and engag ing jacks, line relays for the telephone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuit and to constitute and establish other connections in said shunt conductors, supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, the signal device of each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated, and a pilot signal device included in a conductor portion common to said disconnect signal circuits.

20. In a telephone exchan e system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, disconnect signal circuits corresponding .to the cord circuits, said disconnect signalcircuits having a common portion, a pilot signal device included in said common portion,

and means in association with the telephone lines extraneous to the cord circuits acting in combination with the plugs and jacks to govern the operation of said pilot signal device, said disconnect signal circuits including talking contacts of engaged plugs and jacks.

21. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, disconnect signal circuits corresponding to the cord circuits, said disconnect signal circuits having a common ortion, a pilot signal device included in sai common portion, and line relays in association with the telephone lines acting in combination with the plugs and jacks to govern the operation of the pilot signal device, said disconnect signal circuits including talking contacts of en gaged lugs and jacks.

22. n a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, disconnect signal circuits correspond ing to the cord circuits, each signal circuit including a portion of a talking conductor of a corresponding cord circuit, said disconnect signal circuits having a common portion, a pi ot signal device included in said common portion, and means in association with the.

telephone lines extraneous to the cord circuits acting in combination with the plugs and jacks to govern the operation of said pilot signal device, said disconnect signal circuits including talking contacts of engaged plugs and jacks.

23. In a tele hone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, disconnect signal circuits corresponding to the cord circuits, each signal circuit including a portion of a talking conductor of a corresponding cord circuit, said disconnect signal circuits having a common portion, a pilot signal device included in said common portion, and line relays in association with the telephone lines acting in combination with the plugs and jacks to govern the operation of the pilot signal device, said disconnect signal circuits including talking contacts of engaged plugs and acks.

24. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, disconnect signal circuits corresponding to the cord circuits, each signal circuit includin or adapted to have included as a part thereo a talking conductor of a jack and an engaging contact of a plug, said disconnect signal circuits having a common portion, a pilot signal device included in said common portion, and means in association with the telephone lines extraneous to the cord circuits acting in combination with the plugs and jacks to govern the operation of said pilot signal device, said disconnect signal circuits'including talking contacts of encuit including or adapted to have included as a part thereof a talking conductor of a jack and an engaging contact of 'a plug, said disconnect signal circuits having a common portion, a pilot signal device included in said common portion, and line relays in association with the telephone lines acting in combination with the plugs and acks to govern the operation of the pilot signal device, said disconnect signal circuits including talking contacts of engaged plugs and jacks.

26. In a telephone exchan e system, the combination with telephone dines, of jacks therefor, cord circuits for connection with the jacks, line signal devices for said telehone lines, shunt conductors in connection Q with said line signal devices for effacing the signals they occasion, which shunt conductors include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuit and to constitute and establish other connections in said shunt conductors, and supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, the signal device of each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated, said disconnect signal circuits including talking contacts of engaged plugs and jacks.

27. In a telephone eXchan e system, the combination with telephone %ines, of jacks therefor, cord circuits for connection with the jacks, a pilot line signal device common to said telephone lines, shunt conductors in connection with said pilot line signal device for effacing the signals it occasions, which shunt conductors include registering contacts of plugs of the cord circuits and engaging jacks, ine relays for the telephone lines, said relays having armature switches serving, when 0 erated, to establish the corresponding line signal circuit and to constitute and establish other connections in said shunt conductors, and supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, the signal device of each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated, said disconnect signal circuits including talking contacts of engaged plugs and jacks.

28. In a telephone exchan 'e system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the acks, line signal devices for said telephone lines, conducting media in connection with said line signal devices for effacing the signals they occasion, which media include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, each relay having armature switching mechanism which serves, when operated, to establish the corresponding line signal circuit and to constitute and establish another connection in said conducting media, supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, and a pilot signal device including a conducting portion common to said latter signaling circuits and shunted by the actuated switching mechanisms of the line relays, said .disconnect signal circuits including talkin contacts of engaged plugs and jacks.

29. n a telephone eXchan e system, the combination with telephone Iines, of jacks therefor, cord circuits for connection with the jacks, line signal devices for said telephone lines, shunt conductors in connection with said line signal devices for elfacing the signals they occasion, which shunt conductors include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuit and to constitute and establish other connections in said shunt conductors, supervisoryor disconnect signaling circuits established by plugs and engaging contacts of jacks, and a pilot signal device including a conducting portion common to said latter signaling circuits and shunted by the actuated switching mechanism of the line rela s, said disconnect signal circuits including tal ing contacts of engaged plugs and jacks.

30. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, a pilot line signal device common to said telephone lines, conducting media in connection with said ilot line signal device for effacing the signa ls it occasions, which media include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, each relay having armature switching mechanism which serves, when operated, to establish the corresponding pilot signal circuit and to constitute and establish another connection in said conducting media, supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, and a pilot signal device including a conducting portion common to said latter signaling circuits and shunted by the actuated switching mechanisms of the associated line relays, said disconnect signal circuits including talking contacts of engaged plugs and jacks.

31. In a telephone exchange system, the

combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, a pilot line signal device common to said telephone lines, shunt conductors in connection with said pilot line signal devicefor effacing the signals it occasions, which shunt conductors include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuit and to constitute and establish other connections in said shunt conductors, supervisory or disconnect signaling circuits established by plugs and engaging contacts of acks, and a pilot signal device including a conducting portion common to said latter signaling circuits and shunted by the actuated switching mechanisms of the line relays, said disconnect signal circuits including talking contacts of engaged plugs and jacks.

32. In a telephone exchange system, the combination With telephone lines, of jacks therefor, a cord circuits for connection with the jacks, line signal devices for said telephone lines, conducting media in connection with said line signal devices for eifacing the signals they occasion, which media include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the telephone lines, each relay having armature switching mechanism which serves, when operated, to establish the corresponding line slgnal circuit and to constltute and establish another connection in. said conducting media,

supervisory'or disconnect signaling circuits established by plugs and engaging contacts of jacks, the signal device of 'each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated, and a pilot signal device included in a conductor portion common to said disconnect signal circuits, said disconnect signal circuits including talking contacts of engaged plugs and jacks.

33. In atelephone exchange system, the combination'with telephone lines, of jacks therefor, cord circuits for connection with the jacks, line signal devices for said telephone lines, shunt conductors in connection with said line signal devices for eifacing the signals they occasion, which shunt conductors include registering contacts of plugs of the cord circuits and. engaging jacks, line relays for the telephone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuit and to constitute and establish other connections in said shunt conductors, supervisory or disconnect signaling circuits established by lugs and engaging contact of jacks, the signa device of each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated, and a pilot sig nal device included in a conductor portion common to said disconnect signal circuits, said disconnect signal circuits including talking contacts of engaged plugs and jacks.

34. In a tele hone exchange system, the combination w1th telephone lines, of jacks therefor, cord circuits for connection with the acks, a pilot line signal device common to said telephone lines, conducting media in by the switching mechanism of the corre,

sponding line relay, when said mechanism is operated, and a pilot signal device included in a conductor portion common to said disconnect signal circuits, said disconnect signal circuits including talking contacts of engaged plugs and jacks.

35. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, a pilot line signal device common to said telephone lines, shunt conductors in connection with said pilot line signal device for effacing the signals it occasions, which shunt conductors include registering contacts of plugs of the cord circuits and engaging jacks, line relays for the tele hone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuit and to constitute and establish other connections in said shunt conductors, supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, the signal device of each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated, and a pilot signal device included in a conductor portion common to said disconnect signal circuits, said disconnect signal circuits including talking contacts of engaged plugs and jacks.

36. In a telephone exchange system, the combination with telephone lines, of jacks or connecting switches therefor, cord circuits for connection with the jacks, line signal devices for said telephone lines, shunt conductors in connection with said line signal devices for effacing the signals they occasion, which shunt conductors include registering talking contacts of plugs or switches of the cord circuits and engaging jacks, and

line relays for the telephone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuits and to constitute and establish other connections in said shunt conductors.

37. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, a pilot line signal device common to said telephone lines, shunt conductors in connection with said pilot line signal device for eifacing the signals it occasions, which 'shunt conductors including registering talkmg contacts of plugs of the cord circuits and engaging jacks, and line relays for the tele phone lines, said relays having armature switches serving, when operated, to establish the corresponding line signal circuits and to constitute and establish other connections in said shunt conductors.

38. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits, disconnect signal circuits established by plugs and jacks when in engagement, a pilot disconnect signal common to the disconnect signaling circuits, and means associated with said telephone lines for removing the pilot signal from circuit, said disconnect signaling circuits including talking contacts.

39. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits, disconnect signal circuits established by plugs and jacks when in engagement, a pilot disconnect signal com mon to the disconnect signaling circuits, and means associated with said telephone lines for shunting the pilot signal from circuit, said disconnect signaling circuits including talking contacts.

40. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits, disconnect signal circuits established by plugs and jacks when in engagement, a 'pilot disconnect signal common to the disconnect signaling circuits, and line relays associated with said telephone lines for removing the pilot signal from circuit.

41. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits, disconnect signal cir cuits established by plugs and jacks when in engagement, a pilot disconnect signal com mon to the disconnect signaling circuits, and line relays associated with said telephone lines for shunting the pilot signal from circuit.

42. In a telephone exchange system, the combination with telephone lines, ,of jacks therefor, cord circuits, disconnect signal cir cuits established by plugs and jacks when in engagement, a pilot disconnect signal com mon to the disconnect signaling circuits, and line relays associated with said telephone lines for removing the pilot signal from circuit, said disconnect signaling circuits including talking contacts.

43. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits, disconnect signal circuits established by plugs and jacks when in engagement, a pilot disconnect signal common to the disconnect signaling circuits, and line relays associated with said telephone lines for shunting the pilot signal from circuit, said disconnect signaling circuits including talking contacts.

44. In a telepohne exchange system, the combination with telephone lines,'of jacks therefor, cord circuits for connection with the jacks, line signal circuits for said telephone lines, a pilot signal device common to said line signal circuits, line relays, and shunt conductors in connection with said pilot signal device for effacing the signals it occasions, which shunt conductors include registering contacts of plugs of the cord circuits and engaging jacks and contacts of line relay switches.

45. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, line signal circuits for said telephone lines, a pilot signal device common to said line signal circuits, line controlled means, and shunt conductors in connection with said pilot signal device, whose continuity is governed by said line controlled means and the reglistering contacts of engaged plugs and ac (S.

46. In a telephone exchange system, the combination with telephone lines, of jacks therefor, cord circuits for connection with the jacks, line signal circuits for said telephone lines, a pilot signal device common to said line signal circuits, line relays, and shunt conductors in connection with said pilot signal device for eifacing the signals it occasions, which shunt conductors include registering talking contacts of plugs of the cord circuits and engaging jacks and contacts of line relay switches.

47. In a telephone exchange system, the combination with telephone lines, of jacks or connecting switches therefor, cord circuits for connection with the jacks, line signal circuits for said telephone lines, a pilot signal device common to said line signal circuits, line controlled means, and shunt conductors in connection with said pilot signal device, whose continuity is governed by said line controlled means and the registering talking contacts of engaged plugs or switches and jacks or switches.

48. In a telephone exchange system, the combination with metallic circuit telephone lines, of jacks or connecting switches therefor, cord circuits having metallic sides for connection with the jacks, line signal devices for said telephone lines, conducting media in connection with said lin'e signal devices for efiacing the signals they occasion, which media include registering contacts of plugs or switches of the cord circuits and engaging jacks, line relays for the telephone lines, each relay having armature switching mechanism which serves, when operated, to establish the corresponding line signal circuit and to constitute and establish another connection in said conducting media, and supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, the signaldevice of each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated.

49. In a telephone exchange system, the combination with metallic circuit telephone lines, of jacks or connecting switches therefor, cord circuits having metallic sides for connection with the jacks, a pilot line signal device common to said telephone lines, conducting media in connection with said pilot line signal device for e'flacing the signals it occasions, which media include registering contacts of plugs or switches of the cord circuits and engaging jacks, line relays for the telephone lines, each relay having armature switching mechanism which serves, when operated, to establish the corresponding pilot signal circuit and to constitute and establish another connection in said conductin media, and supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, the signal device of each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated.

50. In a telephone exchange system, the combination with metallic circuit telephone lines, of jacks or connecting switches therefor, cord circuits having metallic sides for connection with the jacks, line signal devices for said telephone lines, conducting media in connection with said line signal devices for effacing the signals they occasion, which media include registering contacts of plugs or switches of the cord circuits and engaging jacks, line relays for the telephone lines, each cuits including talking contacts of engaged plugs and jacks.

51. In a telephone exchange system, the combination with metallic circuit telephone lines, of jacks or connecting switches therefor, cord circuits having metallic sides for connection with the jacks, a pilot line signal device-common to said telephone lines, conducting media in connection with said pilot line signal device for effacing the signals it occasions, which media include registering contacts or plugs or switches of the cord circuits and engaging jacks, line relays for the telephone lines, each relay having armature switching mechanism which serves, when operated, to establish the corresponding pilot signal circuit and to constitute and establish another connection in said conducting media, and supervisory or disconnect signaling circuits established by plugs and engaging contacts of jacks, the signal device of each of which latter circuits being shunted by the switching mechanism of the corresponding line relay when said mechanism is operated, said disconnect signal circuits including talking contacts of engaged plugs and jacks.

In witness whereof, I hereunto subscribe my name this 30th day of April A. D., 1906.

ELMER R. CORWIN. 

